Friday, September 26, 2014

I have long had a particular fascination with birds that live along rushing streams (or, these days, that hang around the dams we build to block them). Life along a torrent poses challenges for birds - in particular, the roar of the waters competes with any sounds the birds make, so signalling others of their kind by voice can be tricky. As a consequence a number of streamside birds have developed combinations of shrill, high-pitched calls and, often, flash-pattern, black-and-white plumage that they show off with tail-wagging or bobbing displays and other stylized movements - with the additional value that this combination of pattern and display can help to conceal the bird from a predator against a background of foam-flecked water.

I am particularly fond of one group of stream birds, the graceful and elegant forktails (Enicurus). Taiwan is home to one I had never seen, so en route to our next stop, Xitou, we stopped off to have a look for it at a spot where Bob had previously photographed a pair. They weren't there when we arrived, but with a bit of patience and some help from a curious passerby we soon located them.

The Little Forktail (Enicurus scouleri) is the smallest and most compact of the forktails, and if it lacks the slim elegance of some of its cousins it is a charming bird nevertheless. You can see how it's striking pattern breaks up the bird's outline when viewed against the background of the light-dappled water. Notice the pink feet! On the Asian mainland, this forktail is a bird of high elevations, above the range of the other species; here in Taiwan, where it is the only one, it can be found - as we found it - lower down.

Forktails are members of the chat/old world flycatcher family. The same family contains other Asian stream birds, and we caught up with two of them once we arrived at Xitou.

One was an old acquaintance: the Plumbeous Redstart (Phoenicurus fuliginosus affinis), a bird I first met many years ago in the Himalayas and have seen again in mainland China. This is an adult male. This bird, with a close cousin from Luzon, is usually placed in a separate genus, Rhyacornis, but a recent molecular study of the chats shows that it belongs with the other redstarts – something, by the way, that I proposed myself in a paper that appeared back in 1979.

It has the distinctive habit of constantly fanning and depressing its tail, something that differentiates it from its cousins but, in my opinion, is simply another example of a streamside bird flash display.

The female Plumbeous Redstart is a very interesting bird. It's plumage is quite different from that of other female redstarts, but looks very much like that of a juvenile. In my old paper I proposed that this was a case of a species that had lost sexual dimorphism (in its closest relatives the male and female are alike), but reacquired it by retaining a modified, greyed out version of its juvenile plumage into adulthood in the female birds. The female, by the way, has white tail patches that it reveals when it fans its tail feathers.

The other stream bird at Xitou was the Taiwan Whistling Thrush (Myiophoneus insularis), an endemic species. While ornithologists have concluded that the chats (such as the forktails and the water redstarts) are more closely related to flycatchers than to thrushes, the idea that these big, robust birds are not thrushes seems counter-intuitive. Nonetheless, the molecular study I referred to earlier shows not only that they are oversize chats, but - even more surprisingly - that their closest relatives are the forktails. Other than their preference for running water, the two groups of birds seem about as different as can be - but that's what the genes tell us. Whistling thrushes lack the flash-pattern plumage of forktails, and can seem downright dull - but perhaps they have another way of drawing attention to themselves.

These photos seem to show a completely different bird from the dull-coloured blackish creature above - but it's the same individual, this time taken with a flash. The result brings out striking structural blues that, I suspect, birders rarely see.

Are these shots unnatural? Or are they showing us something of the brilliance that
other whistling thrushes, who see further into the ultraviolet than we
do and have plumage patches of pure ultraviolet that we cannot see at all, see when they encounter one of their own kind? Is that what gives this bird its "flash"?

Wednesday, September 24, 2014

From Dasyueshan Bob drive Eileen and I deeper into the mountains, as high as the roads reach: to the cold, mist-enshrouded heights of Hehuanshan, above the tree line at over 3000 metres elevation. Here, on April 17, 2013, we searched for some if the special birds of Taiwan's alpine zone.

Perched high in the mountains - so high, in fact, that among its amenities for guests is a supply of oxygen - is Song Syue Lodge, our destination for the night.

At this altitude, at least some of the birds are more typical of Siberia than tropical Asia. There aren't many places this far south where I could be serenaded by a Eurasian Wren (Troglodytes troglodytes taivanus), perched atop a conifer tree behind the lodge.

Here's the wren at ground level, on a bank outside the lodge entrance. Wrens, by the way, are a primarily American family, and there are plenty of species in the New World tropics. In tropical Asia, though it has its share of wrenlike birds - mostly babblers, or something like babblers - this is the only true wren. It used to be considered a member of one wide-ranging species found from Britain (making it the first bird to which the name "wren" was applied) to Alaska and Canada, but the American populations have now not only been split away from the Old World birds, but have been divided into two species themselves, the Winter Wren (T. hiemalis) and the Pacific Wren (T. pacificus).

After breakfast, Bob and I headed to a nearby conifer plantation (listed as Hehuanshanguanli Station on the map) in search of (for me) the most interesting of Taiwan's endemic birds: the Taiwan Firecrest or Flamecrest (Regulus goodfellowi).

First, though, we met another endemic: a male Collared Bush-Robin or Johnstone's Robin (Tarsiger johnstoniae). Obviously this individual has had dealings with people before - the coloured leg-bands are there for individual identification, so someone - I don't know who - has enlisted this bird as part of a population or behavioral study. I'd be curious to know the results.

The White-whiskered Laughingthrushes (Garrulax morrisonianus) here must also be used to people - especially people with food. They descended on us with cries of delight almost as soon as we set foot along the plantation edge.

Birding is a lot easier when the birds come to you!

The Firecrest, Bob told me, was by no means a sure thing - so I was extremely gratified when this one paid us a short visit. Like its cousins elsewhere in the world, this is a bird that keeps on the move. It was all I could do to get a few quick snaps (Bob got some far better ones; you can see them on his Flickr site). There is just enough orange in this bird's crest to make me think this is a male; the bird didn't treat us to the sight of its crest fully erected (something it can do much more spectacularly than the other members of its family).

Firecrests (or kinglets, as we call them in North America) are, as I have said, interesting birds. They belong to a tiny and apparently ancient family, the Regulidae, only half a dozen species of little, active birds whose relatives remain a mystery. They are primarily birds of the northern forests of both the Old and New Worlds, with a few isolated populations (or species, if you prefer) in the Canaries and Madeiras in the Atlantic and this one, the most colourful of the lot, isolated in the highlands of Taiwan.

The Taiwan Fulvetta (Fulvetta formosana), another higher-elevation endemic, has not been recognized as an endemic for long; before 2006 it was considered to be only a subspecies of the Streak-throated Fulvetta (F. cinereiceps). That is not its only recent name-change; it used to be included in the genus Alcippe with all the other "fulvettas", but it turns out (based on molecular studies) that some fulvettas are really relatives of the laughing thrushes (Leiothrichidae) while the others are closer to the parrotbills (Paradoxornithidae). The laughingthrush relatives include the original Alcippe, so they keep that name, but but the others, including this one, have to be renamed - so Fulvetta they are. Anyway, they're very cute.

This plain but active little bird is another victim (if I can use that word) of a recent taxonomic split, though in this case that doesn't convert it, except at the subspecific level, into a Taiwan endemic. The Taiwan form of the Yellow-bellied Bush Warbler (Horornis [or Cettia] acanthizoides concolor) is one of three subpecies; the others are scattered across the mountains of central China and the Himalayas. The species was once included with Hume's Bush-Warbler (Horornis brunnescens) of northern India and Nepal.

Its song is much stranger and more distinctive than its appearance - a series of slow, increasingly high-pitched whistles (followed by a monotone trill) at such a high frequency that I was amazed, at my age, that I could still hear them. Mind you, they must sound a lot louder to other birds than they do to me!

After our successful Firecrest hunt Bob and I headed back to the lodge, where we found a female Collared Bush-Robin. She hopped onto a rock for a better look at us before getting back to the more productive task of poking about in the leaf litter.

By now the fog was closing in, but Bob wanted to show me one more high-mountain specialty before we headed back to less oxygen-starved altitudes. After collecting Eileen, we headed off to a nearby overlook in search of the Taiwan race of the Alpine Accentor (Prunella collaris fennelli). The overlook was fogged in and didn't look over anything, but the bird - undoubtedly expecting a handout from us - was there.

Accentors (Prunellidae), like firecrests, are pretty exotic creatures for a southeast Asian (or, for that matter, a North American) birder. They are confined to the temperate regions of Eurasia; I first came across this species in the Alps. They are rather sombre birds, but their undramatic plumage hides a frantic sexual lifestyle that can involve monogamy, polygamy, polyandry, multiple partners and intense sperm competition. All this was first uncovered in a classic study by Nicholas Davies of the plainest of the lot, the Dunnock or Hedgesparrow (Prunella modularis), amid the spires of Oxford. You can check out the sordid details in Davies' book Dunnock Behaviour and Social Evolution. It's a superb, and enlightening, read.

Visit Ron's Book Blog

Ron and Eileen

I am a Canadian, a wildlife conservationist, naturalist, writer, birder and all-around fortunate fellow. I have been able to make use of my experiences in my books about science, nature and conservation.
I live in Canada, but thanks to my wife Eileen Yen I now spend part of each year in Sarawak, Malaysia.